1. Field of the Invention
The present application relates to a bi-directional driver, in particular, the application relates to a bi-directional circuit for driving a thermo-electric cooler (hereafter denoted as TEC).
2. Related Prior Arts
The TEC implemented with Peltier elements may choose a function to cool down or heat up a device mounted thereon by the direction of the current flowing. The TEC is often driven by, what is called, an H-bridge circuit (hereafter called merely as an H-bridge).
The H-bridge has an arrangement of a pair of two transistors, where these transistors are connected in series between a power supply and the ground (GND). The TEC is connected between intermediate nodes of the two transistors and driven by the PWM (Pulse Width Modulation) signal. That is, a PWM signal drives two transistors diagonally connected with respect to the TEC to provide a PWM current to the TEC. The direction of the current to the TEC may be changed by switching the transistor pair diagonally connected thereto and the power supplied to the TEC may be adjusted by the period of the PWM signal. A Japanese Patent Application published as JP-2006-040370A has disclosed such an H-bridge driver for the TEC.